The present invention relates to a portable power working machine, such as a chain saw, a power cutter, a hedge trimmer and the like. Such machines ordinarily have a top handle, which is usually gripped by the operator with his right hand, and a side handle, which is usually gripped with his left hand. The handles are attached to a main housing. A working member, such as a saw chain or a cutter, extends forwardly from the main housing.
In a conventional portable power working machine of the aforementioned kind, the top handle is constituted by a top grip member, which is located above and oriented parallel to a top surface of the main housing and extends in the longitudinal direction of the main housing. The front and rear ends of the top grip member are connected with the front and rear end portions of the upper surface of the main housing, respectively. The side handle is generally a C-shaped tubular body, one end of which (the upper end) is secured to the main housing close to the front end of the top grip member, and the other end of which (the lower end) is secured to a bottom portion of the main housing, at a location vertically below where the upper end is secured to the main housing. Both ends of the side handle are secured to the main housing at about the same location in the longitudinal direction of the main housing, and therefore, the side handle lies in a vertical plane orthogonally intersecting the longitudinal direction of the main housing.
In the operation of the portable power working machine of the type described above, the working position (or posture) thereof is not necessarily the same all the time, but may be required to be varied depending on the working condition. For example, the operator may sometimes hang the working machine from a branch of a tree using a rope, for instance. Depending on the working posture, the operator may have difficulty suitably gripping the side handle, which, as mentioned above, lies in a vertical plane orthogonally intersecting the longitudinal direction of the main housing, thereby badly affecting the working efficiency.
With a view to solving the above problem, there has been proposed, as set forth in Japanese Patent Publication No. 2931234 (U.S. Pat. No.5,570,512), a portable power working machine (a chain saw) wherein the aforementioned other end (lower end) of the side handle is secured to a lower edge portion of the proximal (rear) end of the main housing, and the central portion of the side handle is curved downwardly diagonally, as viewed from the side.
Although the side handle can be easily gripped, irrespective of the working posture of the machine, the vibrations of the top handle and the main housing are transmitted to the side handle, inasmuch as the other end (lower end) of the side handle is secured to a lower edge portion of the proximal (rear) end of the main housing (recoil starter case). Hence, the operator is not able to sense an integrity between the top and side handles, thus diminishing the operability of the machine. Furthermore, since part of the side handle extends over the main housing, it is required, when performing maintenance or repair work on components housed inside the main housing (such as maintenance and inspection of the prime mover and the recoil starter), to dismount the side handle from the top handle as well as from the main housing, thereby making the performance of maintenance inconvenient.
The present invention has been made in view of overcoming the aforementioned problems. It is an object of the present invention to provide a portable power working machine having a side handle that is easy to grip, irrespective of the working posture of the machine. It is a further object to minimize the transmission of vibrations of the main housing to the side handle, thereby giving the operator a feeling of integrity between the top and side handles and improving the operability of the machine. Another object is to make it easier for the operator to perform maintenance work on the components housed inside the main housing.
With a view to attaining the aforementioned objects, there is provided, according to the present invention, a portable power working machine which includes a main housing having a front end portion, a working member that extends forwardly from the front end portion of the main housing, and a prime mover housed in the main housing. A top handle is secured to the main housing. The top handle is L-shaped as viewed in side elevation and has a top grip portion disposed above and extending parallel to a top surface of the main housing and in the longitudinal direction of the main housing. A rear coupling portion of the top handle extends from the top grip portion downwardly along the rear side of the main housing. The front end of the top grip portion is connected with the front end portion of the top surface of the main housing. A rear coupling portion of the top handle is coupled with a rear end portion of the main housing. A side handle includes a front grip portion, which extends horizontally and laterally from the vicinity of the front end of the top grip portion of the top handle, and a diagonal grip portion, which curves laterally and downwardly from the front grip portion and then extends diagonally straight, as viewed in side elevation, toward the lower end of the rear coupling portion of the top handle. A starting footstool is contiguous to a lower end of the diagonal grip portion and extends horizontally to the vicinity of the lower end of the rear coupling portion. One end portion of the front grip portion of the side handle is connected directly to or molded integrally with the top grip portion of the top handle at a location near the front end thereof. A rear end portion of the starting footstool is connected directly to or molded integrally with the rear coupling portion of the top handle at a location near the lower end thereof.
In preferred embodiments of the portable power working machine according to the present invention, the starting footstool is molded integrally with the side handle.
In a preferred embodiment, said one end portion of the front grip portion of the side handle is connected directly to the top grip portion of the top handle by a bolt or the like, and the rear end portion of the starting footstool is connected directly to the rear coupling portion by a bolt or the like.
Preferably, the starting footstool is configured in plan view such that the outer side wall thereof gradually converges from the front end portion thereof toward the vicinity of the rear end portion thereof so as to make it gradually approach the main housing.
In another preferred embodiment, a vibration isolating member is interposed between the vicinity of the front end of the top grip portion of the top handle and the top surface of the main housing.
In a further preferred embodiment, a vibration isolating member is interposed between the lower end of the rear coupling portion of the top handle and a lower end portion of the rear end portion of the main housing.
In a further preferred embodiment, the diagonal grip portion of the side handle has an oval cross section whose inner circumference has a larger radius of curvature than that of the outer circumference thereof.
The present invention is applicable to such portable power working machines as chain saws, power cutters, hedge trimmers, etc. In the case where the working machine is a chain saw, the working portion thereof is constituted by a saw chain set comprising a guide bar attached to the main housing and a saw chain trained around the guide bar.
According to a preferred embodiment of the portable power working machine, which is constructed according to the present invention, the top handle is L-shaped in side elevation and is constituted by a top grip portion which is located above and parallel to the top surface of the main housing and extends in the longitudinal direction of the main housing and by a rear coupling portion, which extends from the top grip portion toward the rear side of the main housing. The front end of the top grip portion is connected with the front end portion of the top surface of the main housing, and the rear coupling portion is coupled with the rear end portion of the main housing. Furthermore, the side handle is constituted by the front grip portion which extends horizontally and laterally from the vicinity of the front end of the top grip portion and by the diagonal grip portion which curves down from the front grip portion and then extends diagonally straight, in the side view thereof, from the front grip portion toward the lower end of the rear coupling portion. The end portion of the front grip portion of the side handle is connected directly to or molded integrally with the portion of the top grip portion of the top handle which is located close to the front end of the top grip portion.
Further, preferably, the starter footstool is formed integrally with and contiguous to the diagonal grip portion (or a lower end thereof) of the side handle. Since the starter footstool is disposed in this manner, the working machine can be firmly fixed in place by placing one""s foot on the starter footstool on the occasion of pulling the recoil starter handle, thereby facilitating the starting of the working machine.
Furthermore, since the starter footstool extends horizontally to the vicinity of the lower end portion of the rear coupling portion and the rear end portion of the starter footstool is connected directly to or molded with the lower end portion of the rear coupling portion, the side handle is enabled, via the starting footstool, to be connected directly to or molded integrally with the lower end portion of the rear coupling portion. As a result, it is possible to make it easy to grip the side handle (the front grip portion and the diagonal grip portion) irrespective of the working posture of the machine. Further, it is possible, with a portable power working machine embodying the present invention, to give the operator a feeling of integrity between the top and side handles, thus making it possible to improve the operability of the machine as compared with the conventional portable power working machine wherein the other end (lower end) of the side handle is secured directly to a lower edge portion of the proximal (rear) end of the main housing (recoil starter case).
Furthermore, since it is no longer required, when performing maintenance on the components housed inside the main housing (such as maintenance and inspection of the prime mover and the recoil starter), to dismount the side handle from the top handle, the maintenance work can be facilitated.
Additionally, since a vibration isolating member is interposed between the vicinity of the front end of the top grip portion and the top surface of the main housing, and at the same time, since a vibration isolating member is interposed between the lower end of the rear coupling portion of the top handle and a lower end portion of the rear end portion of the main housing, vibration of the top and side handles can be minimized, thus giving the operator a feeling of improved integrity and making it possible to improve the operability of the working machine.